1. Technical Field of the Invention
The present invention relates to a lighting system, for vehicles, that specifies turning-on/off and that also specifies the quantity of light of a plurality of dimmer lamps with radiated ranges that are different from each other, wherein the dimmer lamps are provided at the front of a vehicle in its moving direction, and further wherein the lighting system changes the combination of radiated ranges of said lamps to realize light distribution control.
2. Related Art
There is known a lighting system adapted to enhance the safety of driving on a winding road at nighttime by detecting the steering angle of a vehicle and changing the direction of radiation of lamps according to the change in the steering angle.
3. Problems that the Invention is to Solve
However, said related art system only performs control by continuously changing the direction, of part of the radiation, according to the steering angle of a vehicle running on a winding road. Thus, it is difficult to provide sufficient illumination on road signs, pedestrians, the next vehicle ahead, oncoming cars, or obstacles.
Another related art, as the Japanese Patent Laid-Open No. 238576/2000, proposes a lamp apparatus (a lighting system for vehicles) that specifies turning-on and turning-off, and the quantity of light, of a plurality of dimmer lamps with radiated ranges which are different from each other, wherein the dimmer lamps are provided at the front of a vehicle in its moving direction, and further wherein the lamp apparatus changes the combination of radiated ranges of said lamps to realize light distribution control.
However, the lighting system according to the Japanese Patent Laid-Open No. 238576/2000 presented additional problems that a predetermined lamp, generally a lamp on the wheel steering side suddenly comes on during driving on a winding road, thus surprising pedestrians. Also, in such a system, the driver""s view suddenly becomes clear in the direction where the vehicle is turning, thus perplexing the driver.
The invention, made in view of the problems of the above-described related art, aims at providing a lighting system for vehicles that controls the direction and range of radiation by changing the combination of radiated ranges by a plurality of lamps according to the steering angle of a vehicle, wherein the lighting system gradually controls the increase/decrease in the quantity of light in the radiated area by gradually increasing or decreasing the quantity of light of the lamps to turn them on or off.
In the present invention, in order to attain the above and other purposes, a lighting system for vehicles according to a first aspect of the invention includes:
a plurality of dimmer lamps provided at the front of the vehicle in its moving direction, the lamps being disposed on the vehicle so that the radiated range of each of the lamps is adjacent to that of another in one of right and left directions, wherein the quantity of radiation of each lamp is variable;
a steering sensor for detecting the steering angle of the vehicle; and
radiation control means for changing the combination of radiated ranges of the lamps to achieve light distribution ahead and sideways of a vehicle by specifying turning-on and turning-off of the plurality of lamps, and also by specifying the quantity of light of each lamp, according to the steering angle as detected by the steering sensor,
wherein the radiation control means is adapted to sequentially turn on lamps having respective predetermined radiated ranges ahead, and to the side, of a vehicle according to the steering angle as detected by the steering sensor, and
further wherein the radiation control means is adapted to increase and decrease the quantity of radiation of each lamp according to the steering angle.
Relative data on the lamps to turn on, and their quantity of radiation according to the wheel steering angle is preset as tabular data in the radiation means. When the wheel is turned, the radiation control means computes the control data corresponding to the steering angle data provided by the steering sensor and based on said relative data. The radiation control means, based on the computed control data, sequentially turns on lamps having respective predetermined radiated ranges ahead and to the side of a vehicle according to the wheel steering angle.
In this way, lamps having respective predetermined radiated ranges sequentially come on from ahead of a vehicle to the steering direction (the vehicle""s turning direction) according to the wheel steering angle to illuminate the vehicle""s turning direction. Since the quantity of radiation of the lamps that come on increases according to the steering angle, the brightness of the radiated range in the vehicle""s turning direction gradually increases without suddenly increasing, thus preventing the driver from being perplexed.
In a second aspect of the invention, a lighting system for vehicles according to the first aspect of the invention is characterized in that said radiation control means is further adapted to turn on a first one of the plurality of lamps, and then turn on other ones of the plurality of dimmer lamps having adjacent radiated ranges while the first lamp is still on.
Since other lamps having adjacent radiated ranges turn on while the first lamp is on, the radiated range is seamlessly expanded.
In a third aspect of the invention, a lighting system for vehicles according to the first or second aspect of the invention is characterized in that said radiation control means is further adapted to turn on a first one of the plurality of dimmer lamps, and then to sequentially turn on other ones of the plurality of dimmer lamps whose radiated ranges are adjacent from right to left while controlling the quantity of radiation of the first lamp.
Since the quantity of the adjacent radiated ranges increases as the quantity of light in the radiated range of the first lamp increases, the radiated range corresponding to the area ahead of a vehicle in its moving direction is seamlessly expanded in either right or left directions while gradually increasing in brightness.
In a fourth aspect of the invention, a lighting system for vehicles according to either the first or second aspects of the invention is characterized in that said radiation control means is further adapted to turn on a first one of said plurality of dimmer lamps, and then to sequentially turn on other ones of said plurality of dimmer lamps whose radiated ranges are adjacent from right to left, about at the same time as the quantity of radiation of the first lamp is set to a maximum.
Since the quantity of light of other lamps whose radiated ranges are adjacent from right to left increases about at the same time as the quantity of radiation of the first lamp reaches the maximum, the radiated range corresponding to the area ahead of a vehicle in its moving direction is seamlessly expanded in either right or left directions while gradually increasing in brightness.
In a fifth aspect of the invention, a lighting system for vehicles according to any of the first through fourth aspects of the invention is characterized in that said radiation control means is further adapted to turn on each of the plurality of dimmer lamps at respective predetermined steering angles, to increase the quantity of radiation of each lamp as the steering angle increases, and to maintain, once the quantity of radiation of the lamp has reached a predetermined value, the quantity of radiation of the lamp at the predetermined value irrespective of an increase in the steering angle.
The more the wheel is turned (i.e., the greater the steering angle), the radiated range ahead of the steering direction becomes brighter and is maintained at a substantially constant quantity of radiation until the wheel is returned to a predetermined steering angle position. This makes it easier to detect pedestrians or obstacles.
In a sixth aspect of the invention, a lighting system for vehicles according to any of the first through fourth aspects of the invention is characterized in that said radiation control means is further adapted to turn on each of the plurality of dimmer lamps at respective predetermined steering angles, to increase the quantity of radiation of each lamp as the steering angle increases, and to lower, once the quantity of radiation of the lamp has reached a predetermined value, the quantity of radiation of the lamp according to an increase in the steering angle.
Since the quantity of radiation of a lamp having the radiated range in the direction corresponding to the wheel steering angle (ahead of a vehicle in its moving direction) is at the maximum and other lamps have small radiated ranges, the area in the vehicle""s turning direction is the brightest thus providing excellent visibility and reducing power consumption.
In a seventh aspect of the invention, a lighting system for vehicles according to any of the first through sixth aspects of the invention comprises a vehicle speed sensor that detects the speed of the vehicle, characterized in that said radiation control means is further adapted to control the quantity of radiation of said plurality of dimmer lamps according to the vehicle speed by controlling the quantity of radiation of said plurality of dimmer lamps so that the quantity of radiation of the radiated area ahead of a vehicle becomes smaller and the quantity of radiation of the radiated area sideways of the vehicle becomes larger as the vehicle speed becomes lower, and by controlling the quantity of radiation of the plurality of dimmer lamps so that the quantity of radiation of the radiated area ahead of a vehicle becomes larger and the quantity of radiation of the radiated area sideways of the vehicle becomes smaller as the vehicle speed becomes higher.
In case control of the radiated area is made according to the wheel steering angle without varying the quantity of radiation of lamps, the driver senses a smaller dispersion of light responsive to wheel steering when the vehicle speed is low. On the other hand, the driver senses a larger dispersion of light responsive to wheel steering when the vehicle speed is high. This phenomenon is generally caused because the driver""s field of view is wider at a lower vehicle speed and is narrower at a higher vehicle speed.
However, by controlling the quantity of radiation of dimmer lamps so that the quantity of radiation of the radiated area ahead of a vehicle becomes smaller and the quantity of radiation of the radiated area sideways of the vehicle becomes larger as the vehicle speed becomes lower, and by controlling the quantity of radiation of the dimmer lamps so that the quantity of radiation of the radiated area ahead of a vehicle becomes larger and the quantity of radiation of the radiated area sideways of the vehicle becomes smaller as the vehicle speed becomes higher, the driver senses a constant dispersion of light responsive to wheel steering irrespective of the vehicle speed. Thus, a difference in sensing of dispersion of light responsive to wheel steering, caused by a difference in the vehicle speed, is canceled.
In an eighth aspect of the invention, a lighting system for vehicles according to any of the first through seventh aspects of the invention further comprises an illumination control mode selector switch for selecting, by a plurality of stages, one of a plurality of levels of quantity of radiation of all of said plurality of dimmer lamps, wherein said radiation control means is further adapted to control the quantity of radiation of the plurality of dimmer lamps based on the illumination control mode selected via said illumination control mode selector switch.
For example, it is possible to select the illumination control ratio of each lamp between three illumination control modes, a high illumination control mode whose maximum output is 100 percent, a medium illumination control mode whose maximum output is 80 percent, and a low illumination control mode whose maximum output is 60 percent. The driver selects the low illumination control mode when driving in a very bright place where city lights are numerous, the high illumination control mode when driving in a very dark place such as a mountain road, and the medium illumination control mode when driving on a road having medium brightness. Thus, it is possible to control the quantity of radiation of lamps based on a proper illumination control mode where the quantity of radiation is not wasted.
In a ninth aspect of the invention, a lighting system for vehicles according to any of the first through eighth aspects of the invention, further comprises a turn signal lamp switch, and is characterized in that said radiation control means is further adapted to control the quantity of radiation of a predetermined one of the plurality of dimmer lamps to provide the maximum quantity of radiation of said one lamp when the turn signal lamp switch is turned ON, irrespective of the wheel steering angle.
The turn signal lamp switch is turned on some time, not immediately, before the vehicle makes a turn. In connection with the turn signal lamp switch being turned ON, the quantity of radiation of a predetermined lamp (a lamp that illuminates a predetermined radiated range ahead in the vehicle""s turning direction) reaches the maximum before wheel steering irrespective of the wheel steering angle, thus brightly illuminating the area ahead of a vehicle in its turning direction.
In a tenth aspect of the invention, a lighting system for vehicles according to any of the first through ninth aspects of the invention is characterized in that said lighting system for vehicles further comprises variable optical axis lamps whose optical axes vary in right and left directions in connection with the wheel steering angle.
By additionally using variable optical axis lamps whose optical axes vary in connection with the wheel steering angle, a more proper light distribution control during driving is achieved.
That is, using only variable optical axis lamps may result in light distribution being interrupted by a mechanical driver that drives the optical axis right and left, thus limiting the range of light distribution control. On the other hand, using only a structure where a plurality of dimmer lamps are sequentially turned on via illumination control, said lamps having radiating ranges adjacent to each other and said structure adapted to vary the quantity of radiation of the lamps, does not provide a seamless variation in light distribution. Thus, by combining both approaches (variable optical axis lamps and a plurality of dimmer lamps), it is possible to realize a desirable predetermined light distribution in terms of driving as well as to vary light distribution seamlessly.
In an eleventh aspect of the invention, a lighting system for vehicles according to the tenth aspect of the invention is characterized in that said variable optical axis lamps are composed of headlamps mainly radiating the area ahead of a vehicle, and in that said dimmer lamps are composed of auxiliary lamps for illuminating the areas ahead of and around a vehicle, wherein the auxiliary lamps include: sub lamps for mainly radiating white lines on a road or shoulders; sideways radiating lamps having a radiated range from diagonally ahead to sideways of a vehicle; and lamps for radiating the area in the diagonally forward direction having a radiated range located between that of said sub lamps and that of said sideways radiating lamps.
The optical axis of a headlamp (radiated range) varies in right and left directions in connection with the wheel steering angle, auxiliary lamps having radiated ranges corresponding to the steering direction (vehicle""s turning direction) sequentially come on, and the quantity of radiation of the auxiliary lamps that come on gradually increases according to the steering angle. Thus, the area ahead of a vehicle in its moving direction (vehicle""s turning direction) is illuminated brightly and the brightness of the quantity of radiation in the vehicle""s turning direction does not vary suddenly. This approach is thus less perplexing to the driver.